Quassel is a modern, cross-platform, distributed IRC client, meaning that one (or multiple) client(s) can attach to and detach from a central core -- much like the popular combination of screen and a text-based IRC client such as WeeChat, but graphical.
The core configuration will be done through GUI when connecting the first client (quassel-client).
Before connecting, we should generate a certificate (this exemple sets the validity for 1 years, after which it needs to be reissued, just change the -days to another value if you so desire):
As this is a self-signed certificate, you can type whatever you want in the fields.
Quassel-core operates on port 4242, prepare accordingly if a firewall rule is needed on your setup.
Start the core and add to boot
Start the client and connect to core.
Accept your self-created certificate.
Now set up your IRC-servers and IRC-nicknames on the core.
As this is the first time you connected to the core, you should see a wizard where you can set up the first user-account.